<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .a {
            width: 300px;
            height: 300px;
            background-color: #f00;
            position: relative;
        }

        .a1 {
            width: 300px;
            height: 300px;
            background-color: #ff0;
            position: absolute;

            transform: scale(0);
            transition: 1s;
        }

        .a:hover .a1 {
            transform: scale(1) rotate(360deg);
        }
    </style>
</head>

<body>
    <div class="a">
        <div class="a1"></div>
    </div>
</body>

</html>